The present invention is directed to a hoisting apparatus, and more particularly to a pump jack hoisting apparatus which includes a safety railing for protecting the workers from accidental falling.
In building industry, it is common to erect scaffolding in relation to the structure being built or worked on in order to allow workers to stand at an elevation above the ground surface. A scaffolding system may be utilized, for example, in the installation of aluminum siding on the exterior of a new or existing house. Scaffolding systems of various nature are also utilized in the construction of high-rise, multistory and other types of commercial buildings. The scaffolding system used in connection with the construction of a multistory building, however, is typically self-standing and is generally known as "tower scaffolding". The scaffolding system utilized in connection with the residential housing, on the other hand, is generally erected by utilizing a pump jack system, which is secured in a spaced relationship to the house, and is typically supported in some fashion by the house or the building structure being built, repaired or maintained.
Pump jack systems are known in the industry. In particular, a pump jack system normally includes a pair of uprights or poles each of which includes a pump jack operably connected thereto. The pump jacks typically include inner and outer support arms or extensions (outriggers) for supporting a work platform for the workers to stand thereon. The pump jacks also include pedal operated cranks to elevate the platform on the pump jack poles and often have hand-operated cranks that permit lowering of the platform. The workers standing on the platforms can easily operate the pump jacks to move the platform up and down along the pump jack poles.
As noted above, a pump jack system relies on the building structure for support. In other words, since the inner platform is generally close to the building structure, there generally is no risk for the workers standing on the inner platform of accidental falling. Such is not the case, however, for the workers standing or working on the outer platform. Typically, pump jack systems are not equipped with any types of safety railing either on the edge of the inner platform or on the edge of the outer platform. Since the inner platform is adjacent to the building structure, there has not therefore been a need to provide a railing on the inner platform. There is, however, a need for providing a safety railing on the edge of the outer platform since there is no structure of any kind which would prevent the workers from accidentally falling off from the outer platform.
Although many scaffolding systems and railings for use in connection with various building structures have been proposed in the art, none is specifically directed to or has the configuration and structure for use in connection with a pump jack system. Examples of varies conventional scaffolding systems and railings are disclosed in U.S. Pat. Nos. 3,747,898; 3,867,997; 4,236,698; 4,276,959; 5,307,899; 4,598,794; and 5,314,167.